This invention is an improvement over those contained in U.S. Pat. No. Des. 218,141 and No. 3,654,647, issued in the name of the applicant, in which gripping jaws were first incorporated into a tool of the type comprising the invention. The tool covered by said patents contains practically all of the features of the present invention, but it has since been found that, in actual application, the location of the various elements and their relation to one another is of considerably more importance than was originally thought and the optimum condition has not been Reached in any such multi-purpose tool heretofore, including that of applicant in the mentioned patents. For example, the cutting means positioned to the rear of the pivot axis is not the best location due to awkwardness of trying to cut wire in that position, especially if the wire is already attached to an assembly and is in a relatively restricted location. It has been found that the multiple stripping and crimping operations can be performed with equal facility from either side of the pivot axis as they are usually performed on the loose end of a wire where there is seldom the problem of restricted space. However, the crimping means should take priority over the stripping means in being located nearest the pivot axis due to more force being required to perform the crimping operations. Of course, the cutting, stripping, and crimping means could all be located forward of the pivot axis; but in doing so, other problems are created as will be pointed out hereinbelow in describing the state of the prior art, in which the mechanical advantage of leverage would be lost to some degree.
Another mechanical advantage that has long been recognized and which is desireable in a tool of the type under discussion is a cutting means that utilizes a scissor-like cutting action where one cutting edge bypasses the other in a shearing action, as opposed to a cutting action where the two cutting edges come together in the same plane in abutting relationship. This squeeze-type of cutting action is less effective due to the fact that a nick in either of the cutting edges, or dull cutting edges, will result in an incomplete cut. The same defects, however, have much less effect upon a scissor-type cutter due to the shearing action of the bypassing cutting edges. Consequently, to fully understand the importance of location as well as configuration, one must look at the tools available prior to the instant invention to realize what their shortcomings are and how the present invention is superior in every respect. In a most recent example of the current state of the art, some recognition is given to the importance of location of the operating elements in relation to the pivot axis. However, four of the elements are located forward of the pivot axis and only one is located partly to the rear of the pivot axis (the shearing means, placed in an arc partly around the pivot axis). No elements are placed beyond the flat planar sections immediately surrounding the pivot axis to the rear of the tool. This placement creates a number of problems and disadvantages that cannot be overcome in the concept used. To be more explicit, the concept fails to take full advantage of the leverage principle on both sides of the pivot axis. Instead, four of the five elements are crowded onto the forward side, and in doing so, the space limitation dictated a reduction in the number of a given element that can be used; for example, fewer crimping elements and fewer stripping elements. In addition, the crowding together of most of the elements on the forward side of the pivot axis necessitated the use of the less effective squeeze-type of cutting with abutting cutting edges in order to avoid at least three angular offsets in the forward portions of the tool if the same order of placement were maintained for the elements. That many offsets would not be desireable from a manufacturing standpoint just for the sake of obtaining the scissor-like cutting action. Lastly, the favored location for the best mechanical advantage nearest the pivot axis can only be assigned to one element in this concept, thereby materially reducing the ease with which all of the other elements can be operated.
Other tools using different concepts than the one used as an example have had elements on both sides of the pivot axis, but heretofore there has not been a multi-purpose tool of the type comprising this invention which has brought all of the factors together to take optimum advantage of mechanical leverage combined with the best location for the various elements, and still have a maximum number of elements in the tool for the widest possible application.
A primary object of this invention, therefore, is to provide a multi-purpose tool having all of the necessary functional elements to perform any task connected with an electrical wiring job of whatever nature, including those connected with automotive electrical work, and accomplish this objective in such a manner that the mechanical advantage given to one element will not detract significantly from the mechanical advantage given another requiring near equal force application.
A related object is to locate the operating elements of the tool in such a manner that each has optimum mechanical advantage, in order of force required to operate it, and without the necessity for eliminating any desireable elements that would add to the utility of the tool.
Another object is to provide such a tool that is fairly simple and attractive in appearance, economical to manufacture, and easy to operate.